Determine airflow obstruction from spirometry. Post-bronchodilator FEV1/FVC < 0.70 defines COPD per GOLD criteria. FEV1/FVC < LLN (lower limit of normal) is preferred by ATS/ERS to avoid over-diagnosing obstruction in the elderly.
GOLD defines airflow obstruction as a post-bronchodilator FEV₁/FVC < 0.70. ATS/ERS prefer the lower limit of normal (LLN, 5th percentile) from reference equations, which accounts for the normal age-related decline in the ratio — using the fixed 0.70 threshold can over-diagnose obstruction in older adults.
Pattern interpretation: obstruction is FEV₁/FVC < 0.70 with normal or reduced FVC; restriction is FEV₁/FVC ≥ 0.70 with TLC < 80% predicted (spirometry alone cannot confirm restriction — lung volumes are required); a mixed pattern shows FEV₁/FVC < 0.70 with FVC < 80% predicted.
Reference: GOLD 2024 Report; ATS/ERS spirometry interpretation standards.
Determine airflow obstruction from spirometry. Post-bronchodilator FEV1/FVC < 0.70 defines COPD per GOLD criteria. FEV1/FVC < LLN (lower limit of normal) is preferred by ATS/ERS to avoid over-diagnosing obstruction in the elderly
Each component has a specific meaning:
Note: Interpret the fev1/fvc ratio result against the thresholds and context described above.
Enter the spirometry for the scenario you are assessing. Determine airflow obstruction from spirometry. Post-bronchodilator FEV1/FVC < 0.70 defines COPD per GOLD criteria. FEV1/FVC < LLN (lower limit of normal) is preferred by ATS/ERS to avoid over-diagnosing obstruction in the elderly. Use the fev1/fvc ratio result to inform your calculation.